God's ability to forgive "knows no limits" as his mercy frees people from bitterness and despair, Pope Francis said. "The church's forgiveness must be every bit as broad as that offered by Jesus on the cross and by Mary at his feet. There is no other way," he said on Jan. 1, the feast of Mary, Mother of God, and the World Day of Prayer for Peace. On the first day of the new year, Pope Francis opened the last holy door in Rome as part of the extraordinary Holy Year of Mercy. "The door we have opened is, in fact, a Door of Mercy," he said in his homily, referring to the Roman basilica's large bronze doors depicting Mary presenting her resurrected son, Jesus. "Those who cross its threshold are called to enter into the merciful love of the father with complete trust and freedom from fear; they can leave this basilica knowing with certainty that Mary is ever at their side," especially during times of trouble and sorrow, he said. At the church dedicated to Mary and on her feast day as Mother of God, the pope explained how Mary is the mother of mercy because she bore "the very face of divine mercy," the son of God "made incarnate for our salvation." "Mary is an icon of how the church must offer forgiveness to those who seek it. The mother of forgiveness teaches the church that the forgiveness granted on Golgotha knows no limits. Neither the law with its quibbles, nor the wisdom of this world with its distinctions, can hold it back," he said. Mary offers the world Jesus, who in turn, offers that forgiveness which "renews life, enables us once more to do God's will and fills us with true happiness," the pope said. "The power of forgiveness is the true antidote to the sadness caused by resentment and vengeance," which do nothing but "trouble the mind and wound the heart, robbing it of rest and peace."